♪♪ [ Elephants trumpeting ] NARRATOR: All around the planet, billions of animals are on the move... [ Tiger growls ] ...making incredible journeys.

[ Birds chirping ] The most amazing of these... are the smallest.

♪♪ This series uses the latest camera technology to follow six tiny animals on the biggest adventures of their lives... ...as they travel through extraordinary landscapes... ♪♪ ...where every little step counts.

♪♪ ♪♪ The greatest adventures are the smallest.

♪♪ ♪♪ [ Insects chirping ] ♪♪ ♪♪ NARRATOR: Taiwan is home to an animal that inspired legends of underground dragons.

But this is no scaly fire breather.

It's a Formosan pangolin.

And as evening falls, his journey is just beginning.

♪♪ ♪♪ At two years old, he's the size of a pineapple.

It's his first breeding season, but timing is crucial.

He must find a receptive female before peak season ends in few days' time.

As he travels, he leaves his own distinct scent markings, a calling card for any prospective mate.

And his own sensitive nose can detect female pheromones.

[ Birds chirping ] His territory is a tiny patch of forest half a mile wide.

He hasn't found any sign of another pangolin here.

His species is critically endangered, and so he must walk far to find another.

To fuel his journey, he needs food.

And he's very picky about what he eats.

[ Bird calling, pangolin sniffing ] Something has caught his attention.

One of his favorite foods... ...black ants.

He needs to eat 80,000 ants a day to bulk up.

[ Wood cracking ] But woodpiles are dangerous places to root around.

♪♪ A disturbed Taiwanese cobra can strike in the blink of an eye.

[ Pangolin sniffing ] ♪♪ ♪♪ Flicking its tongue, the snake can taste the pangolin's odor.

Just one drop of its venom could kill a human.

But it would be a mistake to try and bite a pangolin.

His body is covered by snake-proof scales made of the same material as a buffalo's horn.

♪♪ ♪♪ [ Birds chirping ] The scent of tree-dwelling ants now draws him upwards.

Being snake-proof does come with its disadvantages.

His suit of armor is heavy, almost a quarter of his body weight.

But it's not enough to stop him from trying.

♪♪ ♪♪ His scales overlap to give flexibility.

♪♪ ♪♪ ♪♪ He's primed for rapid feeding with a 16-inch tongue... ...essential for tackling cocktail ants... ...so called by the way they cock their tail when alarmed.

He laps them up by the dozen.

The ants are quick to mobilize... ...fighting back with vicious bites.

He has flaps to protect his ears, but the ants are small enough to exploit chinks in his armor.

He's managed to snaffle a few thousand ants.

But their attacks have become too painful to bear.

Time to retreat.

[ Insects chirping ] A nocturnal traveler, he is ready to journey through the night and into the unknown in his search for a mate.

[ Birds calling ] On the opposite side of the world in Brazil's Atlantic Forest... ...dawn is breaking for another endangered species, a family of golden-headed lion tamarins.

This female is 6 years old.

She has made a home here with her lifelong partner.

They are no larger than a milk bottle, but they have a giant responsibility -- three boys under 2 years old... ...and baby twins -- a boy... and a girl.

They are no bigger than the palm of a human hand.

Mom is struggling to provide the milk that they need because the drying climate has made fruit scarce.

[ Birds, insects chirping ] ♪♪ The twins must eat every two days or they could die of starvation.

♪♪ ♪♪ Driven by hunger, the family must travel quickly to find food.

♪♪ Lion tamarins are canopy sprinters.

With claws like running spikes, they dash along the branches, and their forelimbs are like springs boosting their momentum.

They can cover large areas by sprinting in bursts of 25 miles per an hour.

Scientists must use radio collars to follow their journeys.

Carrying babies a quarter of their own weight is exhausting.

They urgently need food.

[ Birds crying ] ♪♪ Black-necked aracari.

Birds have an aerial advantage when it comes to spotting fruit.

They've revealed a hoard of figs.

♪♪ She only needs to eat around 40 to get the calories to produce milk today.

♪♪ But she can smell scent markings.

She's trespassing into someone else's territory.

♪♪ ♪♪ ♪♪ Nervously, they feed as fast as they can.

With food becoming unpredictable, lion tamarins are pushed into more conflict.

[ Tamarins chirping ] The rivals' alarm calls are a sign that they have no intentions of sharing.

And with young babies in tow, it's too risky for the family to stay.

Mom has barely eaten enough.

But at least she can feed the twins with a little milk today.

Yet if they don't get another meal within the next two days, the babies may not make it.

That's not the only threat they face right now.

[ Thunder rumbling, wind whistling ] A storm.

[ Tamarins chirping ] When it rains, the air temperature plummets to 50 degrees.

[ Thunder rumbling ] Hungry and drenched, the babies can't generate heat fast enough.

Hypothermia is a major killer of these tiny monkeys.

But being 10 inches tall does have advantages.

You can hide in the smallest spaces.

And the family huddles inside to keep warm.

[ Thunder rumbling ] Almost four miles from their old home and hungry -- but at least tonight they have somewhere to sleep.

[ Birds crying, insects chirping ] Back in Taiwan, the pangolin is nearly two miles beyond his territory, with no sign of a female.

♪♪ It's critical that he picks up a scent within the next few days.

And very few will be receptive so late in the season.

But his search has taken him into a strange type of forest.

♪♪ ♪♪ There are no trees to climb here.

♪♪ ♪♪ Bamboo -- the tallest grass in the world.

This species can grow three feet in one day.

Here, it towers 65 feet high.

♪♪ Row upon row...mile upon mile.

It's easy to get lost.

♪♪ This is a strange landscape, a plantation created by humans... [ Bamboo creaking ] ...a monoculture.

Nothing but bamboo.

Except... ...the faint scent of a female.

[ Leaves crackling ] ♪♪ The scent has led him into a different type of a forest... [ Birds chirping ] ♪♪ ...an area that's been left wild.

♪♪ And there's a pangolin burrow.

But something doesn't smell right.

♪♪ He must be cautious.

Other animals move into vacant burrows.

[ Animal chattering, whining ] ♪♪ [ Animal chattering, growling ] A gem-faced civet.

[ Birds chirping, calling ] Like a skunk, it can release a stink when alarmed.

Not what you want when your sexual prowess depends on smelling good.

While the pangolin tries to sniff out a mate, another animal here employs a different strategy.

♪♪ Light.

♪♪ ♪♪ ♪♪ There are 56 species of firefly found in Taiwan.

♪♪ ♪♪ ♪♪ Each has its own distinctive sequence of flashes, all used for attracting a mate.

The presence of fireflies is a sign of a healthy habitat.

If the pangolin continues in this direction, he might find more burrows.

♪♪ ♪♪ ♪♪ ♪♪ [ Insects chirping ] ♪♪ As wild habitats are turned to monoculture, fireflies disappear and pangolins find themselves more exposed to humans.

♪♪ ♪♪ Another pangolin burrow.

This time it's empty.

With dawn breaking, at least it's a place to sleep.

[ Vehicle passing ] [ Birds chirping, calling ] The lion tamarins have woken to a new dawn, hungry and far from the fruiting trees that they once called home.

Grooming reinforces the bonds between mom and dad.

[ Birds chirping ] Giant trees are the perfect place to live, full of hiding spaces.

And ahead, there's one of the biggest trees they've ever seen.

♪♪ Its branches support a rich garden of plants.

But the lion tamarins want what might be hiding within.

They don't just eat fruit.

Ten percent of their diet is prey.

[ Birds crying ] ♪♪ ♪♪ Their extended fingers are adapted to reach deep inside.

♪♪ [ Birds chirping, calling ] ♪♪ These grasshoppers are the first proper meal they've had in days.

It's an incredible feast.

But there's even better food here.

Frogs.

[ Water splashes ] Concentrated protein.

♪♪ Mom's got one.

[ Tamarins chirping ] And the whole family are keen for a bite.

♪♪ It's important that mom eats first and replenishes her energy for making milk... ♪♪ ♪♪ ...even if the twins want to try frog for themselves.

♪♪ ♪♪ [ Tamarin chirping ] ♪♪ It's the baby's first taste of solid food.

This is the perfect home for the family -- all the frogs they can eat and no other lion tamarins to compete with.

They could establish a new territory of fruiting trees around it.

[ Birds, tamarins chirping ] The future for the family is looking bright.

With Mom and Dad relaxed, they allow the male twin to take his first steps towards independence.

♪♪ It's a big feat when you are 30 feet off the ground.

♪♪ ♪♪ ♪♪ Two months old, he's learning by copying his older brothers.

But he's not ready to join in on the play fighting just yet.

[ Tamarins chirping ] [ Birds chirping ] All the commotion hasn't gone unnoticed.

♪♪ On the forest floor, predators hunt in the shadows.

♪♪ ♪♪ An ocelot.

It's only twice the size of a house cat, but to the tiny primates, it's a giant and could kill each of them with a single bite.

♪♪ The lion tamarins are unaware of the danger approaching below.

♪♪ ♪♪ The ocelot's speckled coat makes him disappear amongst the undergrowth.

♪♪ ♪♪ His feet are three inches wide, larger than a lion tamarin's head.

They allow him to tread stealthily.

♪♪ And ocelots are agile enough to hunt... in the trees.

[ Birds chirping ] Something isn't right.

[ Tamarins chirping ] The cat's been spotted.

The family needs to abandon the tree quickly.

♪♪ ♪♪ For the ocelot, it's not worth a chase.

He's a nighttime hunter, and this is his sleeping tree, at the heart of his territory, three miles wide.

♪♪ The family must escape from this area quickly.

Come nightfall, the cat will be back on the hunt.

[ Birds chirping, crying ] ♪♪ [ Birds chirping ] In Taiwan, the daytime temperature can reach 100 degrees -- too uncomfortable for a heavily armored pangolin.

He hides in the burrow, where it's 20 degrees cooler.

[ Insects chirping ] As dusk approaches, he can get back to his journey.

♪♪ Out there is the female who dug this burrow, and her scent is growing stronger.

He's entered an olive grove... ...and is deep in a world transformed by humans.

He has never been so exposed.

[ Pangolin sniffing ] [ Dog barking in distance ] ♪♪ In Taiwan, feral dogs pose the biggest threat.

They're one of the few animals able to bite through the pangolin's armor.

[ Barking continues ] ♪♪ [ Armor clanks ] ♪♪ [ Pangolin sniffing ] ♪♪ Finally -- a female.

♪♪ ♪♪ Instinct now takes over.

♪♪ ♪♪ Gently stroking her back, he seeks approval.

♪♪ But the more he makes his advances, the tighter she curls up.

♪♪ She's not interested... a sign that she may already be pregnant.

He's too late.

♪♪ ♪♪ With time running out on the season, he must continue if he is to find another female.

♪♪ Fortunately, he's within reach of a remarkable place.

Taoist shrines are believed to bestow good luck upon all who pass, and they are often found close to a protected forest where pangolins thrive.

[ Birds chirping ] Back in Brazil, The lion tamarins have spent the last five days jumping between thousands of trees.

[ Foliage rustling ] But they have yet to find anywhere safe with enough food to make a home.

♪♪ Suddenly, something that they have never seen before -- a break in the tree cover.

[ Engines humming ] A road.

Here, they are more exposed to aerial threats.

[ Bird screeching ] A monkey-eating harpy eagle, 15 times the weight of a lion tamarin.

With nightfall fast approaching, the family can't turn back.

They must find a way to cross the open road.

♪♪ The gap here is 30 feet wide -- too far to jump.

[ Engine humming ] ♪♪ And they aren't the only ones stuck here.

A sloth.

♪♪ ♪♪ This overhanging tree could be the family's only way over.

[ Birds chirping ] An aerial attack can come from anywhere.

Mom goes first -- 16 feet in a single bound.

♪♪ The rest of the family must follow.

[ Tamarins chirping ] Five have made it.

Two to go.

♪♪ ♪♪ The eagle's caught something.

It's a sloth.

[ Birds chirping ] All the family are accounted for.

[ Vehicles passing in distance ] They continue their journey for just over a mile, until, suddenly, their path is blocked again.

Having spent their entire lives surrounded by trees, they have reached the edge of the forest.

[ Birds chirping, cows lowing in distance ] Beyond is human territory -- a farm.

The lion tamarins are trapped within one of the few remaining patches of the once-vast Atlantic Forest.

Today only 12% remains.

♪♪ Traveling along the forest edge... ♪♪ ...there's nothing for them out there.

It's a dead end for the family.

♪♪ [ Tamarin chirping ] When forest fragments become too small, there's not enough food to sustain a healthy population of animals.

The whole ecosystem begins to collapse.

It's the end of five days searching for a new home... ...and the Tamarins' future seems as uncertain as ever.

[ Birds crying ] For the pangolin, it's now coming towards the end of the breeding season.

He's crossing the boundary into a protected forest, one of thousands scattered across Taiwan, covering nearly 20% of the island.

[ Monkeys barking ] Here, dogs are kept out.

Reserves like this are home to the world's densest population of pangolins -- as many as 25 in a square mile.

But before he continues, he needs to find food and replenish his energy.

Termites -- packed with protein.

[ Birds chirping, calling ] ♪♪ He isn't the only one that's hungry.

[ Animal huffing, pangolin sniffing ] ♪♪ A moon bear, Taiwan's largest carnivore -- 30 times bigger than a pangolin.

♪♪ [ Bear growls ] ♪♪ They usually live high in the mountains.

But in the spring, these bears travel down to lower slopes to seek food.

[ Bear huffing ] ♪♪ They're built for ripping apart trees, with powerful muscles and two-inch-long claws.

♪♪ [ Bear growling ] It could crunch a pangolin in one bite.

It isn't going to give up without a meal.

♪♪ The pangolin takes his chance to get away.

Luckily, he's not what the bear is after.

[ Bear sniffs ] It's the termites.

He needs to find a meal that the bear can't reach.

♪♪ Cocktail ants -- again.

♪♪ ♪♪ ♪♪ [ Monkeys barking ] There's only one scent that can entice a young male away from food.

The pheromones of a female.

This could be his chance.

♪♪ [ Pangolin sniffing ] She is in the last few days of her reproductive cycle.

Soon she will be unable to get pregnant.

The final stage of his journey is now led by this female.

It's a good sign.

They travel hour after hour through the night.

[ Birds crying ] He has proved himself worthy.

♪♪ ♪♪ Mating in a suit of armor isn't easy.

Finding the right angle could take till morning.

♪♪ His first great journey is a success.

He's found a mate.

♪♪ And, safe in this protected forest, he can help to ensure the survival of his species.

[ Birds crying ] ♪♪ Seven months later... ♪♪ ...the pangolins' baby is born.

And the story continues... ...with a new generation ...and a new journey.

♪♪ [ Birds chirping, crying ] It's morning in Brazil.

The tamarins are still traveling along the forest edge.

And now they are being watched.

♪♪ ♪♪ Mom isn't sure what to make of these monkeys.

♪♪ [ Monkeys chirping ] ♪♪ These are Wied's marmosets, a distant cousin of tamarins.

[ Monkeys chirping ] Remarkably, they speak a similar language and can understand each other.

They too are homeless and have babies to feed.

it gives them a unique opportunity to join forces.

♪♪ ♪♪ The lion tamarins take the high branches and keep watch for aerial threats.

[ Tamarins chirping ] The marmosets keep an eye out down below for predators on the prowl.

♪♪ One has spotted an agouti... ...a giant rodent three times bigger than a lion tamarin.

It searches for food with its nose like a dog and stores nuts in the ground like a squirrel.

[ Birds chirping ] Both families follow it, watching where it stores its stash.

[ Tamarins chirping ] The agouti has led them to a new world of opportunity... ♪♪ ...a place of strange plants... ...and huge, colorful fruits.

A cocoa pod... with enough cocoa beans to feed a lion tamarin for a day.

♪♪ ♪♪ This is a territory with plenty of food to go around.

[ Birds chirping ] ♪♪ For both families, it's a paradise.

As they travel further, they discover the most remarkable fruit of all... ...the biggest of any tree on Earth.

This is jackfruit.

It's as big as a basketball... and five times bigger than a lion tamarin.

The fruit on a single tree is packed with enough calories to feed 6,000 golden-headed lion tamarins for the day... ...the entire world population.

♪♪ ♪♪ The family has made it to a part of the forest known as cabruca... ♪♪ ...a place where people sustainably grow cocoa and fruit in the shade of giant native trees.

[ Birds chirping ] ♪♪ Every year, thousands of new trees are planted... ...to connect dying forest fragments... ...making them bigger to keep them alive.

♪♪ The lion tamarins can now play their part to enrich these new areas by spreading seeds in their droppings.

[ Birds chirping ] ♪♪ Cabrucas across the Atlantic Forest are sanctuaries for almost every golden-headed lion tamarin.

♪♪ Here they grow bigger, healthier... ...and produce more babies.

♪♪ [ Tamarins chirping ] ♪♪ The family has discovered a new home on the edge of their world.

And they are already playing a vital role in protecting the forest for future generations.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit PBS.org.

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